Compounders frequently reinforce polymeric or resinous materials with glass fibers. A very lightweight size composition typically coats the fibers to protect them from abrasion damage during processing and handling. The size compositions also tightly bind the fibers and integrate them into multi-fiber bundles or strands. The size also enhances the interaction between the fibers and matrix which they reinforce.
One of the industry's uses for glass fibers is as gun roving which desirably consists of a plurality of continuous strands. A winding operation weakly integrates the strands together with each strand consisting of a plurality of glass fibers. The gun roving then feeds through a chopper associated with a gun which sprays a fluid resin composition. The chopper and gun spray resin and chopped roving together onto a mold. The strands separate and imbed in the fluid resin. Cooling and curing subsequently solidify the combination into a molded part.
U.S. Pat. No. 4,473,618 discloses a substantially chrome-free aqueous sizing composition for glass fiber gun roving which comprises (A) a mixture of emulsified film-forming polymers comprising a polymer of vinyl acetate and ethylene, a polymer of vinyl acetate and an epoxy-functional vinyl monomer, and an unsaturated polyester resin; (B) titanium acetyl acetonate; (C) a silylated polyaminopolyamide hydrochloride or hydrolysate thereof; (D) a cationic lubricant; and (E) 3-methacryloxypropyltrimethoxysilane or hydrolysate thereof.